Publications by authors named "Tomohiro Takiguchi"

This study aimed to clarify (1) the association among the atrial fibrillation (AF) type, sleep-disordered breathing (SDB), heart failure (HF), and left atrial (LA) enlargement, (2) the independent predictors of LA enlargement, and (3) the effects of ablation on those conditions in patients with AF. The study's endpoint was LA enlargement (LA volume index [LAVI] ≥ 78 mL/m).Of 423 patients with nonvalvular AF, 236 were enrolled.

View Article and Find Full Text PDF

The presence of epicardial connections (ECs) between the pulmonary veins (PVs) and atrium may contribute to atrial fibrillation (AF) recurrence. This study aimed to determine the impact of sleep-disordered breathing (SDB) on the presence of ECs and the interplay between SDB and ECs on AF recurrence.We retrospectively reviewed 400 consecutive non-valvular AF patients.

View Article and Find Full Text PDF

Background: A balloon-based visually guided laser balloon (LB) ablation (LBA) is as effective and safe as radiofrequency ablation and cryoballoon ablation in curing patients with atrial fibrillation (AF). The third-generation LB is so compliant that it can be inflated to any pressure and size change of up to 41 mm with its maximal expansion, which enables maximum balloon/tissue contact regardless of the size or shape of each pulmonary vein (PV) ostium. A large common inferior trunk (CIT) with a structured, completely independent common ostium of both the right and the left inferior PVs completely conjoined prior to the junction with the left atrium is an extremely rare anatomical variant and an important triggering focus in paroxysmal AF.

View Article and Find Full Text PDF
Article Synopsis
  • The study investigates the effectiveness of data-driven respiratory gating (DDG) in detecting subcentimeter lung lesions using a digital PET/CT system.
  • Utilizing various phantom spheres of different sizes, the researchers compared the image quality and lesion detectability across three groups: stationary imaging, imaging with respiratory motion, and imaging with DDG applied.
  • Results indicated that while DDG did not identify new lesions, it significantly improved image quality and quantitative metrics for lesions larger than 6 mm, enhancing visual detection scores in the process.
View Article and Find Full Text PDF

Background: The existence of epicardial connection(s) (ECs) between the pulmonary veins (PVs) and atrium may hinder establishing a complete PV antrum isolation (AI) (PVAI) in patients with atrial fibrillation (AF). Thus, the purpose of this study was to determine the prevalence and location of ECs inside the conventional PVAI lines.

Methods and results: Three-hundred consecutive patients with non-valvular AF were evaluated.

View Article and Find Full Text PDF
Article Synopsis
  • The study investigates how patient body size influences image quality and quantitative values in bone SPECT imaging, following guidelines first established in 2017.
  • Using specially designed phantoms to simulate different body sizes, the research measures contrast, noise, and uptake values across various acquisition times.
  • Findings reveal that larger body sizes result in decreased image quality, requiring longer acquisition times to achieve the same results as smaller sizes, indicating the importance of considering body habitus in SPECT imaging.
View Article and Find Full Text PDF

Angiotensin II (Ang II) reportedly facilitates primary tumor growth and distal hematogenous metastasis formation in various murine intravenous metastasis models. However, it is unclear whether Ang II accelerates the initial processes of metastasis formation that begins in primary tumors surrounded by tumor microenvironment. We examined the effects of Ang II on primary tumors and lung metastasis lesions using a murine spontaneous metastasis model, in which triple negative breast cancer 4T1 cells constitutively expressing luciferase (4T1-Luc cells) were injected into the mammary fat pad of BALB/c mice.

View Article and Find Full Text PDF

Purpose: The AI-300 automated infusion device (Sumitomo Heavy Industries, Ltd., Tokyo, Japan) is subject to administration error as a function of smaller volumes of F-FDG dispensed via a three-way cock supplied with a disposable kit. The present study aimed to validate the administration accuracy of the AI-300 using an improved disposable kit for quantitative positron emission tomography (PET) assessment.

View Article and Find Full Text PDF

Objectives: To establish a new three-dimensional quantitative evaluation method for bone metastasis, we applied bone single photon emission tomography with computed tomography (SPECT/CT). The total bone uptake (TBU), which measures active bone metastatic burden, was calculated as the sum of [mean uptake obtained as standardized uptake value (SUV) above a cut-off level] × (the volume of the lesion) in the trunk using bone SPECT/CT. We studied the threshold value and utility of TBU in prostate cancer patients treated with radium-223 (Ra-223) therapy.

View Article and Find Full Text PDF

Objective: The present study aimed to reveal the influence of combination of different collimators and energy windows on the planar sensitivity and the spatial resolution during experimental Ra imaging, and to determine optimal imaging parameters.

Methods: A vial type source containing Ra solution (4.55 MBq / 5.

View Article and Find Full Text PDF

Objective: The present study aimed to clarify gross tumor volume (GTV) contouring accuracy at the diaphragm boundary using respiratory-gated PET/CT.

Methods: The lung/diaphragm boundary was simulated using a phantom containing F solution (10.6 kBq/mL).

View Article and Find Full Text PDF

Purpose: Several cross-calibration schemes have been proposed to produce quantitative values in bone SPECT imaging. Differences in the radionuclide sources and geometric conditions can decrease the accuracy of cross-calibration factor (CCF). The present study aimed to validate the effects of calibration schemes using different sources under various geometric conditions.

View Article and Find Full Text PDF

The relationship among blood pressure (BP) levels at discharge, other multifaceted factors assessed in cardiac rehabilitation programs, and prognosis for up to 2 years was examined in 154 consecutive cases (132 patients; 69 males; 79 ± 12 years, mean ± SD). A total of 72 composite events occurred (58 rehospitalizations from cardiovascular causes and 14 all-cause death events). The relationship between the systolic BP (SBP) at discharge and the long-term prognosis formed a J-shaped curve, with the event rate being lowest in patients with SBP of 115-125 mmHg.

View Article and Find Full Text PDF

Guidelines for the management of hypertension have recommended strict control of blood pressure to help prevent cardiovascular disease. The aim of the present study was to evaluate the current status of blood pressure control and trends over the past two decades. Four hundred patients treated for hypertension at Kyushu University Hospital were included in the present study.

View Article and Find Full Text PDF

Objective: The present study aimed at determining the quantitative accuracy of phase-based respiratory-gated PET/CT imaging using phantom and clinical studies.

Methods: The effects of target size, target-to-background ratio (TBR), and respiratory motion on PET images were estimated using a NEMA body phantom comprising six spheres (diameter 10-37mm) in a solution of F-18 of three different TBRs (4, 6, 8). The phantom was moved in a superior-inferior direction at motion displacements of 0, 10, 20 and 30 mm.

View Article and Find Full Text PDF

Objective: To evaluate a computer-assisted diagnosis system, BONEVAVI version 2 for bone scintigraphy, this study examined the performance of the software in patients with and without skeletal metastasis.

Methods: Bone scans of various patients were analyzed by BONENAVI version 2. Patients with skeletal metastasis from prostate cancer, lung cancer, breast cancer, and other cancers were included in the study as true positive cases.

View Article and Find Full Text PDF

Objective: High-energy beta emitters such as Strontium-89 ((89)Sr) and Yttrium-90 ((90)Y) are becoming increasingly popular nuclear therapy sources in Japan for treating cancer. Various characteristics of materials must be considered when designing radiation protection device for high-energy beta emitters. We empirically measured and simulated dose equivalents of beta and bremsstrahlung radiation arising from (89)Sr and (90)Y radiation shielded with various materials and determined optimal shielding materials against these sources.

View Article and Find Full Text PDF

Objective: PET images are affected by scanner model, reconstruction conditions, injected dose, scan duration, patient health status and FDG radiopharmaceutical supply systems. The present study compares images of 40 patients using commercial and in-house FDG systems with one PET scanner (Aquiduo).

Methods: The PET images were evaluated using the physical indexes of NECpatient, NECdensity and SNRliver proposed by the Japanese guidelines for oncological FDG-PET/CT, and by visual assessment.

View Article and Find Full Text PDF

Quality control (QC) detects changes in the performance of gamma cameras that could adversely affect interpretations of clinical studies. We used plate and sheet (57)Co flood sources to measure extrinsic uniformity during daily QC. Each source, when placed on the top of a collimated detector, allowed the acquisition of uniform images from both detectors, thus reducing the amount of time needed to perform daily QC.

View Article and Find Full Text PDF

Objectives: Accurate calibration of dose calibrators (DC) is required for quantitative positron emission tomography (PET) studies to generate meaningful information. Values measured by DC depend not only on the radioactive nuclide but also the environment where measurements are taken. Therefore, DC must be calibrated at each location.

View Article and Find Full Text PDF

The image quality in (18)FDG PET/CT often degrades as the body size increases. The purpose of this study was to evaluate the relationship between image quality and the body size using original phantoms of variable cross-sectional areas in PET/CT. We produced five water phantoms with different cross-sectional areas.

View Article and Find Full Text PDF

Image misregistration can occur in fusion PET/CT, because of motion artifacts caused by the management of respiration. The standard imaging protocol of the CT component of PET/CT is normal expiration (NormExp) or free breathing (FB). The objective of this study was to compare NormExp and FB for the optimal breathing protocol for PET/CT scans.

View Article and Find Full Text PDF

Background: Radioguided sentinel node biopsy (SNB) of breast cancer patients has become a standard method for detecting early stage breast cancer. However, no standard radiopharmaceutical exists.

Methods: 99mTc rhenium colloid or 99mTc phytate SNB was used to aid detection in breast cancer patients.

View Article and Find Full Text PDF